14,635 research outputs found
Large magneto-optical Kerr effect in noncollinear antiferromagnets Mn ( = Rh, Ir, or Pt)
Magneto-optical Kerr effect, normally found in magnetic materials with
nonzero magnetization such as ferromagnets and ferrimagnets, has been known for
more than a century. Here, using first-principles density functional theory, we
demonstrate large magneto-optical Kerr effect in high temperature noncollinear
antiferromagnets Mn ( = Rh, Ir, or Pt), in contrast to usual wisdom.
The calculated Kerr rotation angles are large, being comparable to that of
transition metal magnets such as bcc Fe. The large Kerr rotation angles and
ellipticities are found to originate from the lifting of the band
double-degeneracy due to the absence of spatial symmetry in the Mn
noncollinear antiferromagnets which together with the time-reversal symmetry
would preserve the Kramers theorem. Our results indicate that Mn would
provide a rare material platform for exploration of subtle magneto-optical
phenomena in noncollinear magnetic materials without net magnetization
Entropy Estimate for Degenerate SDEs with Applications to Nonlinear Kinetic Fokker-Planck Equations
The relative entropy for two different degenerate diffusion processes is
estimated by using the Wasserstein distance of initial distributions and the
difference between coefficients. As applications, the entropy cost inequality
and exponential ergodicity in entropy are derived for distribution dependent
stochastic Hamiltonian systems associated with nonlinear kinetic Fokker Planck
equations.Comment: 22 page
Kinetic behavior of the general modifier mechanism of Botts and Morales with non-equilibrium binding
In this paper, we perform a complete analysis of the kinetic behavior of the
general modifier mechanism of Botts and Morales in both equilibrium steady
states and non-equilibrium steady states (NESS). Enlightened by the
non-equilibrium theory of Markov chains, we introduce the net flux into
discussion and acquire an expression of product rate in NESS, which has clear
biophysical significance. Up till now, it is a general belief that being an
activator or an inhibitor is an intrinsic property of the modifier. However, we
reveal that this traditional point of view is based on the equilibrium
assumption. A modifier may no longer be an overall activator or inhibitor when
the reaction system is not in equilibrium. Based on the regulation of enzyme
activity by the modifier concentration, we classify the kinetic behavior of the
modifier into three categories, which are named hyperbolic behavior,
bell-shaped behavior, and switching behavior, respectively. We show that the
switching phenomenon, in which a modifier may convert between an activator and
an inhibitor when the modifier concentration varies, occurs only in NESS.
Effects of drugs on the Pgp ATPase activity, where drugs may convert from
activators to inhibitors with the increase of the drug concentration, are taken
as a typical example to demonstrate the occurrence of the switching phenomenon.Comment: 19 pages, 10 figure
Self-partitioning SlipChip for slip-induced droplet formation and human papillomavirus viral load quantification with digital LAMP
Human papillomavirus (HPV) is one of the most common sexually transmitted infections worldwide, and persistent HPV infection can cause warts and even cancer. Nucleic acid analysis of HPV viral DNA can be very informative for the diagnosis and monitoring of HPV. Digital nucleic acid analysis, such as digital PCR and digital isothermal amplification, can provide sensitive detection and precise quantification of target nucleic acids, and its utility has been demonstrated in many biological research and medical diagnostic applications. A variety of methods have been developed for the generation of a large number of individual reaction partitions, a key requirement for digital nucleic acid analysis. However, an easily assembled and operated device for robust droplet formation without preprocessing devices, auxiliary instrumentation or control systems is still highly desired. In this paper, we present a self-partitioning SlipChip (sp-SlipChip) microfluidic device for the slip-induced generation of droplets to perform digital loop-mediated isothermal amplification (LAMP) for the detection and quantification of HPV DNA. In contrast to traditional SlipChip methods, which require the precise alignment of microfeatures, this sp-SlipChip utilized a design of “chain-of-pearls” continuous microfluidic channel that is independent of the overlapping of microfeatures on different plates to establish the fluidic path for reagent loading. Initiated by a simple slipping step, the aqueous solution can robustly self-partition into individual droplets by capillary pressure-driven flow. This advantage makes the sp-SlipChip very appealing for the point-of-care quantitative analysis of viral load. As a proof of concept, we performed digital LAMP on an sp-SlipChip to quantify human papillomaviruses (HPVs) 16 and 18 and tested this method with fifteen anonymous clinical samples
Efficacy and safety of Latanoprost/Timolol fixed combinations in treatment of refractory glaucoma following vitrectomy in short period
AIM: To evaluate the efficacy and safety of Latanoprost/Timolol fixed combinations(LTFC)in treatment of refractory glaucoma following vitrectomy in short period.<p>METHODS: In the present study, 42 eyes of 38 refractory glaucoma patients who had received vitrectomy were carried out. The patients were randomly divided into two groups after a 2-week washout period for previous antiglaucoma medication. Patients in group 1 underwent a 6-week treatment with LTFC and those in group 2 were treated with Latanoprost/Timolol unfixed combinations(LTuFC)for 6 weeks. The IOP, visual field, and mRNFL were measured after the washout period as the baseline, and after 6 weeks of therapy. Eye condition and adverse reactions were observed. <p>RESULTS: The mean baseline IOPs of groups 1 and 2 were respectively 37.90±3.74mmHg and 37.57±3.23mmHg. After 6 weeks, the mean IOPs were respectively 30.10±4.90mmHg and 30.62±4.62mmHg, indicating a significant reduction from the baseline(<i>t</i>=12.16, <i>t</i>=13.78, <i>P</i><0.01). No difference was observed in the IOP reduction between LTFC and LTuFC(20.54%±7.88%, 18.23%±7.03%, <i>t</i>=0.75, <i>P</i>>0.05). IOP reduction was 24.87%(20 eyes), 17.46%(15 eyes), and 9.65%(7 eyes)respectively among those with open-angle glaucoma, with partially open-angle glaucoma, and with closed-angle glaucoma. The eye drops didn't have effects on the vision field and mRNFL(all <i>P</i>>0.05), and their main adverse reactions were eye irritation and mild hyperemia.<p>CONCLUSION: In refractory glaucoma, especially in open-angle or partially-open-angle glaucoma, LTFC, administered after vitrectomy, helps to reduce IOP with desirable safetly and tolerance
Orbit- and Atom-Resolved Spin Textures of Intrinsic, Extrinsic and Hybridized Dirac Cone States
Combining first-principles calculations and spin- and angle-resolved
photoemission spectroscopy measurements, we identify the helical spin textures
for three different Dirac cone states in the interfaced systems of a 2D
topological insulator (TI) of Bi(111) bilayer and a 3D TI Bi2Se3 or Bi2Te3. The
spin texture is found to be the same for the intrinsic Dirac cone of Bi2Se3 or
Bi2Te3 surface state, the extrinsic Dirac cone of Bi bilayer state induced by
Rashba effect, and the hybridized Dirac cone between the former two states.
Further orbit- and atom-resolved analysis shows that s and pz orbits have a
clockwise (counterclockwise) spin rotation tangent to the iso-energy contour of
upper (lower) Dirac cone, while px and py orbits have an additional radial spin
component. The Dirac cone states may reside on different atomic layers, but
have the same spin texture. Our results suggest that the unique spin texture of
Dirac cone states is a signature property of spin-orbit coupling, independent
of topology
Probucol reduces the cerebral edema area and infarction volume in rat cerebral infarction model via PI3K/Akt pathway
Purpose: To study the effects of probucol on rats with cerebral infarction through the phosphatidylinositol 3-hydroxy kinase (PI3K)/protein kinase B (Akt) pathway.Methods: Sprague-Dawley (SD) rats were divided into sham group (SO group, n = 7), model group (MO group, n = 7) and probucol group (PR group, n = 7). Infarction volume, messenger ribonucleic acid (mRNA), protein expressions of PI3K/Akt, neurological score, brain water content, degree of brain tissue lesions and neurological function score were determined.Results: Neurological score was 0, 2.54 ± 0.67 and 1.34 ± 0.21 points, in SO, O and PR groups, respectively. In turning angle test, neurological function score gradually rose at 24 h after cerebral infarction in PR and MO groups, compared with that in the SO group (p < 0.05), but significantly declined at 48 h in PR group compared with that in MO group (p < 0.05). Brain water content was lowest in the SO group but highest in MO group; it was significantly lower in PR group than that in MO group (p < 0.05). The mRNA and protein expressions of PI3K/Akt were highest in SO group and lowest in MO group; the expressions were higher in PR group than those in the MO group (p < 0.05).Conclusion: Probucol reduces the cerebral edema area and infarction volume by activating PI3K/Akt pathway, thereby exerting a significant therapeutic effect on rat model with cerebral infarction. Thus, this agent has the potential for use in the management of cerebral infarction
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